The move allows the more adventurous to install any app of their choosing, not just those approved by Apple to appear on the App Store. For the technically minded the development opens up the possibility of examining the device's filesystem or installing services such as a secure remote login server (sshd).

On the downside, jail-breaking comes with a number of risks including the potential to open devices to a greater threat of attack from hackers and malware.

The jailbreak works on iPad 2 or an iPhone 4S running iOS 5.0.1.

Jail-breaking is legal in most territories (including the US), but going through the process would void warranties. Tools to carry out the modification were developed by hardware enthusiast group Green Poison. More details on the hack can be found here. ®